Date of Award

8-16-2024

Document Type

Open Access Thesis

Department

Biological Sciences

First Advisor

James Pinckney

Abstract

Vibrio parahaemolyticus is a pathogenic bacterium whose full impact on natural estuarine phytoplankton communities has not been fully resolved. The primary goal of this research was to test how the addition of V. parahaemolyticus to a natural estuarine microbial community would impact the other microbes present. We hypothesized V. parahaemolyticus exposure would reduce phytoplankton biomass and alter the composition of phytoplankton and bacterial communities. Experimental bioassays (60h) were used to assess the effects of the presence of V. parahaemolyticus . Samples for measurements of chemotaxonomic photopigment concentrations, 16S sequencing-based community composition, photosynthetic efficiency, cell density, and V. parahaemolyticus abundance were collected throughout the incubation. There was a significant difference between the exposed- and nonexposed-groups for chl-a, indicating a decrease in overall phytoplankton biomass. ChemTax analysis also revealed there was a decrease in the relative abundances of diatoms, cryptophytes, and cyanobacteria. There was also a change in bacterial community composition, with eight phyla decreasing in relative abundance and one phyla increasing in relative abundance. These results suggest V. parahaemolyticus may have a significant impact on microbial communities in estuarine ecosystems and should be closely monitored, as changes in microbial communities can result in ecological and chemical changes in habitats; in addition, the seafood industry should test for the presence of V. parahaemolyticus in their products, especially during the summer months when phytoplankton and bacterial populations thrive.

Rights

© 2024, Sarah Mulligan

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